In recent years, the dispensing of fresh water to fowl or small animals has increasingly been provided by the use of demand actuated water dispensers directly connected to a fresh water supply. A dispenser adapted for watering swine is generally comprised of a metal valve secured to a water supply line and formed of a corrosion resistant metal. Included in the valve is a displaceable valve actuator in the form of a spring biased elongated stem extending beyond the valve body at its distal end. The animal wanting to drink envelopes his mouth about the valve end and displaces the distal end of the stem. The stem is capable of being displaced by the animal in opposition to a light spring force to an offset position during which fresh water is automatically dispensed. The animal soon learns to operate the valve by tongue and when drinking is completed the stem is released enabling a spring force to revert the stem to its shutoff relation.
In order to control the flow rate of water being dispensed when the valve is actuated, it has been known to utilize various intervening control devices such as an adjustable orifice plug in which the flow area can be selectively varied on site. An adjustably settably device for varying the rate of water flow is disclosed in U.S. Pat. No. 4,370,948. Most commonly, the water source to be passed by the valve is well water from which filtering of sediment or ground particulates if any has been minimal. Consequently, there has been a tendency for the initially open orifice to become constricted or even blocked in service so as to require frequent maintenance in the form of replacement or cleanout as appropriate.
Exemplifying demand-type animal watering devices of the prior art are the disclosures of U.S. Pat. Nos. 2,939,424; 3,777,714; 3,698,431; 4,187,804; 4,370,948; 4,416,221; 4,491,088 and 4,573,433.
Because swine in particular are inclined to eat or at least chew almost anything that is chewable including soft metal or plastics, the tendency in the industry has been to form valves of stainless steel which is both too hard to be edible or chewable and yet very resistant to corrosion. Valves of that type are commercially available under the trademark Pig Nip. While stainless steel has been highly suitable for the end purpose, stainless steel as a base commodity has recently incurred some substantial price increases. The price increases have of course been passed on to the fabricator and then to the consumer and as a result the market price of the finished valve has increased significantly beyond the price at which it was previously available.
While the industry is well aware of the problem, it has not been heretofore known how to reduce material costs while rendering the valve inedible or chew resistant to the animals for which they are provided.